I would like to rig an alarm system that would use a cell phone to dial out and transmit an alarm. Mostly concerned if we leave our dogs in the coach and the air conditioning fails for some reason.There are lots of inexpensive dialers for land lines but I only found one so far online and it was almost $1000.

There are car theft alarms that send a radio signal to a small receiver you carry in your pocket. Perhaps something like that could be adapted to your needs. I don't know what sort of range you would need. But if you are going to stay within a mile or two of the bus it might be something to consider.

Telephone dialers are older technology. Newer cell phone dialers do not dial pagers or consumer telephones. They are digital and transmit digital information that is received by a receiver (computer) and decoded. An operator then is given the info on a computer screen.

I sell cellular technology communicators for the residential and business intrusion market. Someone may have the device your are looking for. I have not seen it.